Chlorine dioxide is utilized in a variety of processes including a large number of bactericidal applications, especially in the fields of water treatment and odor abatement. Its usage is continuing to grow for many reasons. Due to the unstable nature of gaseous chlorine dioxide when compressed it is necessary to produce chlorine dioxide on site rather than to produce it at a plant and ship it for useage when needed. The prior art processes involve the production of chlorine dioxide by the reaction of a chlorite with a diluted hydrochloric acid, followed by introduction into the water system to be treated.
Procedures for the manufacture of chlorine dioxide which have been previously proposed, especially those utilizing the chlorite/hydrochloric acid process, require the use of elaborate generation equipment that includes means of diluting the hydrochloric acid or they involve the use of plant personnel to dilute the hydrochloric acid which is a hazardous undertaking. Often these procedures require the use of an additional catalyst such as Potasium Persulfate or Potasium Perborate adding to the expense, and also can contaminate the chlorine dioxide with unwanted by-products. Also they require the use of excessive amounts of hydrochloric acid from 200 to 325% in excess of the stoichiometric weight requirements; this also adds another unnecessary expense. Others also require the careful control of the reaction temperature, which makes the reaction difficult to control, and complicates the equipment necessary.
We have found that all of these problems can be overcome, and that a superior method of generating chlorine dioxide in a safe manner may be achieved by utilization of the process of the present invention.
It is therefore a principal object of this invention to provide a process for the preparation of chlorine dioxide which is relatively simple, is safe, uses commercially available chemicals in their concentrated form, requiring no pre-dilution, and achieves consistently high yields.
Still another object of the present invention is to provide a process that requires only a chlorite and hydrochloric acid, and is not dependent on an expensive catalyst.
Another object of the present invention is to provide a process for the production of chlorine dioxide which is very economical by requiring substantially less hydrochloric acid to obtain high yields.
Still another object is to provide a process which is not dependent on elevation or control of temperature.
Other objects will become apparent hereinafter.